The present invention relates to an airbag apparatus that inflates an airbag to protect an occupant from an impact that is applied to, for example, a vehicle.
An air bag apparatus is effective for protecting an occupant when an impact is applied to transportation such as a vehicle. One example of an airbag apparatus is disclosed in Japanese Laid-Open Patent Publication No. 2011-168234.
The airbag apparatus includes an airbag 104, which is formed by sewing fabric portions 101 together at peripheries thereof. The airbag 104 has a periphery sewn portion 102, which is formed by the sewing, and an inflation portion 103 surrounded by the periphery sewn portion 102. The periphery sewn portion 102 has two terminals 102a, 102b, which are separated from each other. The terminals 102a, 102b are formed by leaving sections of the peripheries of the fabric portions 101 unsewn. The airbag 104 further has two circular second sewn portions 105. Each second sewn portion 105 is located closer to the center of the inflation portion 103 than the corresponding terminal 102a, 102b of the periphery sewn portion 102, and, at that position, sews the fabric portions 101 to each other. Parts of the second sewn portions 105 that face each other and are closest to each other serve as vent hole defining sections 105a, which define an opening 106a of a vent hole 106.
When the transportation receives an impact, inflation gas G from an inflator 107 is supplied to the interior of the inflation portion 103, so that the airbag 104 is deployed and inflated. The deployed and inflated airbag 104 is located between an occupant and a transportation component that bulges into the transportation, for example, a side door, to restrain the occupant. The excess of the inflation gas G in the inflation portion 103 of the deployed and inflated airbag 104 is discharged to the outside of the inflation portion 103 through the vent hole 106 as indicated by an arrow in FIG. 20. Such restraint of the occupant by the airbag 104 and the drop of the internal pressure of the airbag 104 due to discharge of the inflation gas G through the vent hole 106 reduce the impact transmitted to the occupant via, for example, the side door.
When inflation gas is discharged through the vent hole 106, the second sewn portions 105 prevent the stress of the inflation gas from being concentrated on the terminals 102a, 102b of the periphery sewn portion 102.